The case for burning our way to a cleaner planet

There are myriad proposals to fight climate change, but the simplest and most effective is to leave fossil fuels in the ground — simple in concept, yet elusive in practice, to put it mildly.

Energy reformers face an economic system built on consumption and exploitation, a political system dominated by monied interests, and an energy system built around fossil fuels. As a result, even the most optimistic scenarios for averting climate change call for us to do more than cut carbon pollution — we must provide for “negative emissions,” ways of removing carbon dioxide from the air.

Earth lights from above.Pexels

Enter BECCS, which is short for “bioenergy with carbon capture and storage.” BECCS entails growing plants that remove CO2 from the atmosphere, burning those plants to generate electricity, and then capturing the resulting carbon emissions before they escape into the atmosphere.

The technology is still in its infancy and deeply controversial because it calls for growing fuel on land that could otherwise be used to grow wheat, rice, or corn for human consumption. But there is a new, experimental approach to BECCS that could dispense with the controversy by creating energy with a valuable byproduct — food. Scientists believe the process may not only produce electricity with less planet-heating carbon dioxide but also enough food to nourish billions of people by 2050.

It’s complicated and still conceptual. Nevertheless, it’s an intriguing idea that algae — made with some of the carbon dioxide emitted by burning biomass — can be used to shore up the global food supply at a time when drought, floods, and heat waves, spurred on by climate change, threaten widespread famine in vulnerable regions.

Carbon pollution.Pexels

“Combining two technologies — BECCS and microalgae production — may seem like an odd couple, but it could provide enough scientific synergy to help solve world hunger, and at the same time reduce the level of greenhouse gases that are changing our climate system,” said Charles Greene, professor of earth and atmospheric sciences at Cornell University, who helped develop the model.

Greene’s research colleagues include Colin M. Beal and Mark Huntley from the University of Hawaii, Zackary Johnson of Duke University, and Ian Archibald of Cinglas Ltd, who first came up with the idea. They described their work in a study that appears in Earth’s Future.

A microalgae farm.Cyanotech

BECCS combines growing biofuel crops, such as grasses and oilseeds, with carbon capture and storage. It’s a technology that snatches the CO2 from power plants before it enters the atmosphere, compresses it into a liquid form, then traps it deep underground. While the technology still is evolving, several BECCS projects already are underway.

Some experts urge caution. Climate scientist Philip B. Duffy, president and executive director of the Woods Hole Research Center, warns that counting on BECCS to deliver the planet from catastrophic climate change could be impractical and unworkable. Duffy said the Intergovernmental Panel on Climate Change (IPCC), which includes negative emissions from BECCS in future climate scenarios, has “bet the future of humanity on massive deployment of BECCS.

By ‘bet the future of humanity,’ I mean that their scenarios for limiting global warming to 1.5 or 2 degrees C — the Paris goals — accomplish that only through assuming that BECCS will be used at a truly massive scale. That makes it relatively easy to achieve climate policy goals, because as you know BECCS generates energy and removes CO2 from the atmosphere at the same time. At least that’s the idea. So far it has been tested only at a very small scale, and there are reasons to think it won’t be practical at the very large scale assumed in the models.”

Greene agreed. “Since the last IPCC report, everybody has become excited, both positively and negatively, about BECCS,” Greene said. “The proponents see it as a straightforward way to generate negative emissions — just let terrestrial plants capture CO2 from the atmosphere, burn that biomass in a power plant, capture the CO2 from the stack, and then pump it underground. The naysayers point out that it would require a huge commitment of land to produce the required amounts of plant biomass, and that would take the land away from food production, which is already going to be stressed to the max. So, we came up with Algae + BECCS = ABECCS.”

Here’s how it works. “In ABECCS, you grow eucalyptus trees for biomass, burn it in a power plant, and capture the CO2, just like in BECCS,” Greene explained. “However, instead of pumping all of that CO2 underground to store it, you use a fraction of it to support algae production.

A koala in a eucalyptus tree.Pixabay

The algae can then produce the same amount of food and biofuel as if you were growing soy, but from a much smaller footprint of land. When you add the land for growing the eucalyptus and the land for growing the algae together and then compare it to growing soy on the same amount of total land, you get some interesting results.”

Greene said that 7,000-acre ABECCS facility can yield as much protein as soybeans produce on the same plot of land, while sequestering 30,000 tons of carbon dioxide per year, the equivalent of taking more than 6,000 cars off the road.

“The algae and the forestry could be done on adjacent parcels of land, or they could be done at different locations as long as the transport costs between them are not too large,” he said. “On the Big Island of Hawaii, for example, eucalyptus grows very rapidly on the rainy northeast Hamakua Coast. Less than 50 miles away, marine algae can grow very rapidly in the sunny, desert conditions of the Kona-Kohala Coast. Transport costs between these sites 50 miles apart would make such a project commercially feasible today.”

While nobody has attempted to create an actual ABECCS pilot project anywhere — yet — Greene believes Hawaii “is a great place to conduct a demonstration project, although there are probably other places in the world where the lower prices of land might provide a better commercial opportunity,” Greene said.

The groundwork is there. AES Hawaii already is burning eucalyptus at its power plant in Kalaeloa to test whether the trees can be used as biomass and converted to renewable energy, and a demonstration project for growing algae already exists adjacent to Kona International Airport.

The coast of Hawaii.Pixabay

There is, of course, the problem of selling humans on the idea of eating algae, but as Greene noted, “Algae can be used as a nutritious and tasty alternative to most dairy products, and can replace just about anything that currently uses soy or palm oil.”

He added, “Now, many Americans cannot imagine their diets being shifted primarily to algae, but I can assure you that most of the developing world would prefer to have that algal source of protein than to continue being malnourished.”